Weed Cover Research Articles

Effect of fire on weed dynamics and behavior of pre-emergent herbicides in Eucalyptus spp. plantations

The forest fires that occurred during summer 2021-22 in Uruguay generated concern in several areas, including silvicultural systems. The fire could generate changes at the flora level by changes in the dormancy of soil bank seeds, and in the behavior of frequently used pre-emergent herbicides due to inactivation by ashes. These possible changes impose a challenge in connection to weed control. In this study, an attempt was made to provide an answer to the problem by evaluating the dynamics of weeds and the behavior of pre-emergent herbicides in post-fire Eucalyptus plantations. The evaluations were carried out in two sites previously burned —one of them previously harvested and the other one not, being able to obtain data in different conditions. The weed dynamics was evaluated through the observational study of the percentage of total weed cover and present species were identified. With the data obtained, the parameters frequency, diversity and richness were calculated to analyze the different properties separately. Pre-emergent herbicides were evaluated in a randomized block experimental design: S-metolachlor, flumioxazin + S-metolachlor , isoxaflutole + S-metolachlor, oxifluorfen + S-metolachlor . Proposed treatments were assessed for possible interactions with fire and removal of the first cm of soil and ashes. Weed density was evaluated by characterizing and quantifying how many weeds could emerge in a square 30cm×30cm. While one of the fields was evaluated 8, 23, 31, 41, 61, and 82 days post application (DPA), the other was evaluated 8, 20, 31, 41, and 61 DPA. On both experiments the fire showed an increase in the weeds. In one experiment the weeding percentage increment was 64.9% on the burned area, while on the other it was 54.3 %. In addition, in the non-harvested field there were no large amounts of weeds on both treatments due to the conditions that standing trees generated. The results of weed control did not show interaction between efficiency and ashes presence, and were related to the species present in the weed bank, not showing a clear trend among the herbicide treatments. The S-metolachlor treatment was always the highest in number of weeds. The number of weed|m2 was about 17-25 on the harvested field, and 3-4 weed|m2 on the non-harvested one. The fire generated changes in the expression at seed bank of soil. This study was an important development in the generation of knowledge for future production.

Response of pepper (Capsicum annuum L.) to preemergence application of Oxadiargyl and pendimethalin

Two field experiments were conducted in two agro-ecological zones of Ghana (Forest and Coastal Savannah) to assess the efficacy of preemergence herbicides Oxadiargyl and Pendimethalin on weed incidence, growth and yield of pepper. The experiment was factorial arranged in a randomized complete block design. The treatments were Oxadiargyl at 0.4, 0.5, 0.6 L/ha, Pendimethalin at 1.5, 2.0, 2.5 L/ha and hand weeding at intervals of 3, 6 and 9 weeks as control. Data was collected on weed type and abundance, number of days to weed emergence, type of re-emerging weeds and percentage weed cover. Data on plant height, number of branches per plant, yield and yield components of pepper plants were also collected. Results indicated that application of Pendimethalin led to a significantly (p < 0.05) longer number of days to weed emergence as compared to the application of Oxadiargyl which also delayed weed emergence significantly longer than hand weeding. Plant height was not affected by weed control method. The yield of pepper plants was significantly higher in plots where Pendimethalin (2.0 L/ha) was applied. Generally, the yield components of pepper plants have been positively affected by weed control treatments. However, application of Pendimethalin at 2.0 L/ha resulted in better weed control.

Towards practical object detection for weed spraying in precision agriculture.

Weeds pose a persistent threat to farmers' yields, but conventional methods for controlling weed populations, like herbicide spraying, pose a risk to the surrounding ecosystems. Precision spraying aims to reduce harms to the surrounding environment by targeting only the weeds rather than spraying theentire field with herbicide. Such an approach requires weeds to first be detected. With the advent of convolutional neural networks, there has been significant research trialing such technologies on datasets of weeds and crops. However, the evaluation of the performance of these approaches has often been limited to the standard machine learning metrics. This paper aims to assess the feasibility of precision spraying via a comprehensive evaluation of weed detection and spraying accuracy using two separate datasets, different image resolutions, and several state-of-the-art object detection algorithms. A simplified model of precision spraying is proposed to compare the performance of different detection algorithms while varying the precision of the spray nozzles. The key performance indicators in precision spraying that this study focuses on are a high weed hit rate and a reduction in herbicide usage. This paper introduces two metrics, namely, weed coverage rate and area sprayed, to capture these aspects of the real-world performance of precision spraying and demonstrates their utility through experimental results. Using these metrics to calculate the spraying performance, it was found that 93% of weeds could be sprayed by spraying just 30% of the area using state-of-the-art vision methods to identify weeds.

Transformer in UAV Image-Based Weed Mapping

Weeds affect crop yield and quality due to competition for resources. In order to reduce the risk of yield losses due to weeds, herbicides or non-chemical measures are applied. Weeds, especially creeping perennial species, are generally distributed in patches within arable fields. Hence, instead of applying control measures uniformly, precision weeding or site-specific weed management (SSWM) is highly recommended. Unmanned aerial vehicle (UAV) imaging is known for wide area coverage and flexible operation frequency, making it a potential solution to generate weed maps at a reasonable cost. Efficient weed mapping algorithms need to be developed together with UAV imagery to facilitate SSWM. Different machine learning (ML) approaches have been developed for image-based weed mapping, either classical ML models or the more up-to-date deep learning (DL) models taking full advantage of parallel computation on a GPU (graphics processing unit). Attention-based transformer DL models, which have seen a recent boom, are expected to overtake classical convolutional neural network (CNN) DL models. This inspired us to develop a transformer DL model for segmenting weeds, cereal crops, and ‘other’ in low-resolution RGB UAV imagery (about 33 mm ground sampling distance, g.s.d.) captured after the cereal crop had turned yellow. Images were acquired during three years in 15 fields with three cereal species (Triticum aestivum, Hordeum vulgare, and Avena sativa) and various weed flora dominated by creeping perennials (mainly Cirsium arvense and Elymus repens). The performance of our transformer model, 1Dtransformer, was evaluated through comparison with a classical DL model, 1DCNN, and two classical ML methods, i.e., random forest (RF) and k-nearest neighbor (KNN). The transformer model showed the best performance with an overall accuracy of 98.694% on pixels set aside for validation. It also agreed best and relatively well with ground reference data on total weed coverage, R2 = 0.598. In this study, we showed the outstanding performance and robustness of a 1Dtransformer model for weed mapping based on UAV imagery for the first time. The model can be used to obtain weed maps in cereals fields known to be infested by perennial weeds. These maps can be used as basis for the generation of prescription maps for SSWM, either pre-harvest, post-harvest, or in the next crop, by applying herbicides or non-chemical measures.

On the hydro-geomorphology of steepland coffee farming: Runoff and surface erosion

Soil compaction and natural vegetation removal associated to agriculture tends to promote runoff and soil erosion with potentially adverse onsite, downstream, and global impacts. Although coffee farming represents a fraction of the world’s harvested lands, it is a vital crop for many developing nations where it is frequently cultivated on erosion prone, high-relief, wet tropical landscapes. However, limited empirical data exists on coffee farm erosion. This article attends this need by describing the results of rainfall simulation experiments designed to evaluate the impact of sun-grown coffee-farming on precipitation excess, soil infiltration rates, and surface erosion by overland flow. Results show that infiltration rates on coffee-cultivated fields are ∼60 – 80% relative to undisturbed forested slopes, and that cultivation increases erosion rates by one to two orders of magnitude depending on the presence or absence of mulch or weed cover. The magnitude of the impact suggests that erosion on coffee-cultivated land is unsustainable from both a soil formation and an agricultural productivity point of view. Unsurfaced access roads display an even greater impact than cultivated surfaces with infiltration rates ∼10% of undisturbed soils and erosion up to four-orders of magnitude above background depending on grading history and slope. Farm-scale annualized erosion is ∼3–24 Mg ha-1 yr-1 depending on actively used unpaved road abundance as roads account for ∼99% of net erosion. Implementing efficient erosion control strategies for coffee farms is therefore essential to reduce their current impacts, but also for the future given the worldwide surge in coffee harvesting areas projected for the upcoming decades.

Grass species as a living mulch – impact of sod and its weediness on apple trees

The relationship between a cover of four grass living mulches in an apple orchard and the weed cover as well as its impact on the fruit tree yield, growth, and fruit quality was estimated at the Fruit Experimental Station of the Wrocław University of Environmental and Life Sciences in Wrocław (Poland). The experiment was established in a young orchard of ‘Chopin’ cv. apple trees grafted on rootstock MM 106, i.e. one of the strongest semi-dwarf rootstock. One year after, the tree planting soil was covered by blue fescue, red fescue, Kentucky bluegrass, and perennial ryegrass in tree rows and tractor alleys. The apple trees showed a similar degree of adaptation to the changing cultivation conditions in four different living mulches despite the varied share of the area covered by weeds. However, they did not avoid competition from different grass sods and their weediness, which was reflected in their low yield and low crop efficiency coefficient. The perennial species composition and the percentage share of the most common weeds differentiated the sod of the studied grasses. Among several perennial weed species, &lt;i&gt;Trifolium repens&lt;/i&gt; L. was found to be the most competitive in all grass living mulches. The dynamic development of this species in time was stimulated by a rapid increase in precipitation in the orchard. The lowest soil surface cover by the total weeds was noted soon after the perennial ryegrass emergence due to the rapid development of the grass. Red fescue spread the most efficiently among all the studied grasses, and its coverage allowed effective reduction of the presence of weeds. This cover crop also maintained high purity of grass sod, especially in the tree rows, until the end of the experiment period.

The organic mulches in vineyards exerted an influence on spontaneous weed cover and plant biodiversity

The current trend toward sustainable agricultural practices creates a demand for alternatives to conventional soil management. One of the main problems for farmers is the competition for water and nutrients of weeds with the crop and the complicated management that this entails. Conventional practices such as tillage and the use of herbicides are commonly used and imply high environmental impacts while organic mulches could be an attractive sustainable alternative for soil management. Therefore, the 3-year effect of different soil management practices with organic mulches on the control of spontaneous weeds in the vine row has been studied. Three types of organic mulches [grapevine pruning debris (GPD), straw (SM) and spent mushroom compost (SMC)] and two conventional soil management methods [in-row tillage (TILL) and herbicide (HERB)] were compared on a vineyard in North Spain. For this purpose, the percentage of soil covered by weeds (PWC), the presence of each species and its effect on the vine development, and the weed community formations were analysed in each soil management. In addition, soil nutrition, soil temperature and soil water content were measured. On the one hand, SM and GPD mulches limited the presence of weeds (<30%), reducing the need for tillage maintenance and improving soil integrity. On the other hand, SMC produced excessive weed growth (>85%) that could be a problem for the farmer. Of the conventional practices, the TILL treatment was strongly affected by the timing of agricultural work and environmental conditions, with large variability between years. The results indicated that the application of organic mulches reduced the percentage of species with a harmful effect on optimal vine growth and increased plant diversity and its benefits for the ecosystem. Organic mulches are an effective alternative for soil management due to the improvement of the chemical and physical properties of the soil, the increase in the water content of the soil, the reduction of heat stress and the percentage of noxious species for optimum vine growth.

Synthetic auxin herbicides do not injure intermediate wheatgrass or affect grain yield

AbstractIntermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019 to 2021) at sites in Wisconsin, Minnesota, New York, and North Dakota. This evaluation included broadleaf herbicides registered for use on wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA (all are categorized as Group 4 herbicides by the Weed Science Society of America). Each herbicide or mixture was applied at 1× and 2× the labeled wheat application rate to newly planted and established (1- to 5-yr-old) IWG stands in the fall or spring. Herbicides were applied during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71% to 92% across herbicide treatments relative to the nontreated check at the Wisconsin site, whereas weed control at the Minnesota site was variable among treatments. At the New York site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the North Dakota site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.

Productivity of Finger Millet (Eleusine coracana (L) Geartn) as Influenced by Pre-emergence Herbicides in the Northern Guinea savanna of Nigeria

Two field trials were conducted during 2011 and 2012 wet seasons at the Research Farm of the Institute for Agricultural Research, Ahmadu Bello University, Samaru Zaria (Lat. 11 o 11 1 N, Long. 07 O 38E and 686m above sea level), in the northern Guinea savannah zone of Nigeria, to evaluate the efficacy of pre-emergence herbicides on weed in finger millet. The treatments were atrazine (80WP) at the rates of (0.4, 0.8, 1.2 and 1.6 kg a.i/ha), RafT ® (500SC ) (Atrazine 250 g/l + Terbuthylazine 250 g/l ) at the rates of (0.25, 0.5, 0.75, and 1.0 kg a.i/ha) and Bullet (R) (700SC) (Atrazine 225 g/l + Terbuthylazine 225 g/l + Acetochlor 250 g/l) at the rates of (0.35, 0.75, 1.05 and 1.4 kg a.i/ha), hoe weeded control at 3 and 6 WAS and a weedy check. The treatments were laid out in a Randomized Complete Block Design (RCBD), replicated 3 times. The result shows that all the herbicide treatments significantly reduced weed dry weight than the weedy check. Application of atrazine at 0.8 kg a.i/ha or Raft at 0.5 kg a.i/ha gave lower weed dry weight and weed cover score than the hoe weeded control at 3 and 6WAS.While all the rates of Bullet, Raft at 0.75 and 0.1 kg a.i./ha and atrazine at 1.2 and 1.6 kg a.i./ha resulted in lower weed dry matter production which were comparable to hoe weeded control at 3 and 6WAS. Based on the results obtained from this study, 0.8 kg a.i./ha atrazine or 0.5 kg a.i./ha Raft gave season long weed control over hoe weeded check in finger millet with yield increase of 94.2 and 99.5%, respectively. The weedy checks reduced yield of finger millet by 66.7%.

Alternative integrated weed control with cowpea to improve soil properties

Cover crop (CC) is a ground cover plant. This is one of the strategies to improve soil quality and suppress the use of herbicides. One of the CC is able to survive in a tropical climate and grows well in soil conditions with moderate to low fertility is cowpea. Therefore, this study attempts to examine the benefits of using cowpea as CC to improve soil quality. This research will be conducted with the experimental method. Moreover, this study used a randomized block design with 2 factorials. The first factor was weed control techniques (P), with levels: without weed control (P0), cover crop (P1), pre-emergence herbicides (P2), post-emergence herbicides (P3), and weed-free (by weeding) (P4). And the second factor is tillage technique (T), namely: without tillage (T0) and conventional tillage (T1). Based on the research conducted, it was found that the combination of using CC (P1) and no tillage (T0) treatments were able to improve soil quality, (P1) affects the nitrogen value of the soil due to the presence of root nodules. While the tillage technique (T0) affects the bulk density (BD) which tends to be stable, and the organic-C content is quite restrained due to no evaporation due to tillage.

Intercropping and weed cover reduce sugarcane roots colonization in plant crops as a result of spatial root distribution and the co-occurrence of neighboring plant species

Intercropping and weed cover reduce sugarcane roots colonization in plant crops as a result of spatial root distribution and the co-occurrence of neighboring plant species

Restoring declining species through translocations: A test case using flightless grasshoppers in an urban setting

Abstract Population translocations are used increasingly as a conservation strategy for vertebrates. However, relatively few attempts have been made to translocate invertebrates despite their potential benefits for food webs, and despite the practicality of undertaking such translocations in small areas including urban environments where space is limited. We conducted 36 translocations of 1851 individuals of the generalist flightless grasshopper Vandiemenella viatica across urban Melbourne, where 93% of its original habitat has been lost. We aimed to understand characteristics essential for grasshopper persistence and to investigate detection, occupancy, dispersal and habitat suitability throughout its active period to improve insect translocation success in urban settings using revegetated sites and small remnant habitats. We also measured movement and detection probability after one week in short‐term trials. The one‐week trial indicated that grasshopper sex and colour morph did not influence the probability of detection, and there was no evidence of directional movement by females and males. One year after translocation, V. viatica were found in 28 out of 36 translocation sites. These surveys showed that detection probability changed across survey seasons and was influenced by soil temperature. Also, soil temperature positively affected detection in the winter surveys. Occupancy probability was influenced by graminoid cover, plant species richness and weed cover. We found no evidence of directional movement by females and males in the F1 generation. Abundance and presence/absence data were best explained by graminoid cover and plant species richness. Our findings suggest that wingless grasshopper translocations are feasible in small urban patches of suitable habitat, helping to restore invertebrate biodiversity and ecological services.

Aggregation of organically managed fields promotes aphid parasitism in cereal crops under Mediterranean conditions

ContextMaintaining a balance between semi-natural habitats and arable land is not always feasible for farmers. The promotion of biological control agents can be addressed through management at farm or field level, and/or by deploying lower intensity, biodiversity-friendly practices which can act either directly or indirectly through their effect of the plant community.ObjectivesWe studied the effects on cereal aphids and their parasitoids of agricultural management at field and landscape levels. We tested the effect of organic and conventional farming, and of the within field characteristics, on the cereal aphid-parasitoid community, across a gradient of organic farming aggregation and of percentage of arable land.MethodsIn spring 2015, we sampled aphid populations in 30 cereal fields in five agricultural areas in Catalonia (Spain) with contrasting levels of organic farming aggregation. In each field, we also assessed weed and crop cover. As landscape variables, we calculated the Percentage of Agricultural Land (PAL) and the Percentage of Organically Managed Land (POML) in a 500-m buffer around each field. We sampled cereal tillers 3 m from the field edges and collected all aphids detected. In addition, we reared mummies (parasitized aphids) until they hatched.ResultsOur results show that management at landscape level has significant effects on parasitism rates: a higher proportion of surrounding fields under organic management increased the amount of parasitism, as did less agricultural land cover. On the other hand, aphid populations were mainly affected by two in-field factors, namely, crop density and crop variety. Differences in weed communities did not seem to have any effects on either aphids or parasitoids.ConclusionsRather than concentrating on the individual management of fields, a coordinated implementation of organic farming at landscape level would seem to be a much better strategy for improving the biological control of aphids.

Plant secondary metabolite-dependent plant-soil feedbacks can improve crop yield in the field.

Plant secondary metabolites that are released into the rhizosphere alter biotic and abiotic soil properties, which in turn affect the performance of other plants. How this type of plant-soil feedback affects agricultural productivity and food quality in the field in the context of crop rotations is unknown. Here, we assessed the performance, yield and food quality of three winter wheat varieties growing in field plots whose soils had been conditioned by either wild type or benzoxazinoid-deficient bx1 maize mutant plants. Following maize cultivation, we detected benzoxazinoid-dependent chemical and microbial fingerprints in the soil. The benzoxazinoid fingerprint was still visible during wheat growth, but the microbial fingerprint was no longer detected. Wheat emergence, tillering, growth, and biomass increased in wild type conditioned soils compared to bx1 mutant conditioned soils. Weed cover was similar between soil conditioning treatments, but insect herbivore abundance decreased in benzoxazinoid-conditioned soils. Wheat yield was increased by over 4% without a reduction in grain quality in benzoxazinoid-conditioned soils. This improvement was directly associated with increased germination and tillering. Taken together, our experiments provide evidence that soil conditioning by plant secondary metabolite producing plants can increase yield via plant-soil feedbacks under agronomically realistic conditions. If this phenomenon holds true across different soils and environments, optimizing root exudation chemistry could be a powerful, genetically tractable strategy to enhance crop yields without additional inputs.

Suppression of weed communities by granivores over time in an agroecosystem

AbstractInvertebrate granivore communities can consume numerous weed seeds in cropland, but how this granivory influences weed recruitment over time in continuous no‐till systems is unknown. Weed and surface‐active granivore communities were determined in soybeans (Glycine max) over 3 years in eastern South Dakota. We examined seed removal rates of sentinel redroot pigweed, green foxtail, and lambsquarters (Chenopodium album) seeds and applied gut content analysis of granivores to determine which species consume immuno‐marked seeds of green foxtail (Setaria viridis). Weed stands with low diversity and high biomass production were associated with granivore community complexity. In turn, granivore community complexity was associated with weed communities with low diversity and high biomass in the subsequent growing season. Fall seed consumption, as measured by seed removal rates and gut content analysis of foxtail seed markers, was positively correlated with weed recruitment in the subsequent growing season. Seed specialists behaved differently toward focal weed species than the granivore community at large. Gryllus pennsylvanicus abundance was correlated with higher green foxtail consumption and removal rates. None of the other dominant green foxtail consumers revealed a similar set of responses. We propose a feedback mechanism whereby granivore community complexity in cropland leads to larger but fewer weeds over multiple years. Weed communities with these characteristics then lead to more complex granivore communities. If these relationships persist over time with minimal disturbance in continuous no‐till cropping systems without pesticides, this feedback loop could reduce weed cover.

Environmental factors affecting honey bees (Apis cerana) and cabbage white butterflies (Pieris rapae) at urban farmlands.

Rapid urbanization results in a significantly increased urban population, but also the loss of agricultural lands, thus raising a concern for food security. Urban agriculture has received increasing attention as a way of improving food access in urban areas and local farmers' livelihoods. Although vegetable-dominant small urban farmlands are relatively common in China, little is known about environmental factors associated with insects that could affect ecosystem services at these urban farmlands, which in turn influences agricultural productivity. Using Asian honey bee (Apis cerana) and cabbage white butterfly (Pieris rapae) as examples, I investigated how environmental features within and surrounding urban farmlands affected insect pollinator (bee) and pest (butterfly) abundance in a megacity of China during winters. I considered environmental features at three spatial scales: fine (5 m-radius area), local (50 m-radius area), and landscape (500 m-raidus and 1 km-radius areas). While the abundance of P. rapae increased with local crop diversity, it was strongly negatively associated with landscape-scale crop and weed covers. A. cerana responded positively to flower cover at the fine scale. Their abundance also increased with local-scale weed cover but decreased with increasing landscape-scale weed cover. The abundance of A. cerana tended to decrease with increasing patch density of farmlands within a landscape, i.e., farmland fragmentation. These results suggest that cultivating too diverse crops at urban farmlands can increase crop damage; however, the damage may be alleviated at farmlands embedded in a landscape with more crop cover. Retaining a small amount of un-harvested flowering crops and weedy vegetation within a farmland, especially less fragmented farmland can benefit A. cerana when natural resources are scarce.

Dynamics of Cynodon dactylon and weed community composition in different cover crops in a vineyard

AbstractThe implementation of cover crops in vineyards is an environment‐friendly soil management technique that has several advantages, including weed suppression. The effectiveness of the management depends on the characteristics of both the weed community and the cover crop species. The objectives of this study were to evaluate the dynamics of Cynodon dactylon patches and the rest of the weed community composition under five different cover crops (four grasses and one dicotyledonous species) in a commercial vineyard in Spain: (1) the perennial Festuca arundinacea and the annual species (2) Hordeum vulgare, (3) Vulpia ciliata, (4) a mixture of Bromus species and (5) Medicago rugosa. The annual species were sown in November every year after tillage (from 2015 to 2018) and shredded in June, while F. arundinacea was sown in 2015 and shredded in June and in November every year. Results showed that cover crop species affected C. dactylon soil coverage and frequency across the field. After three seasons, F. arundinacea and H. vulgare were the best cover crops which controlled C. dactylon, resulting in the lowest weed coverage of 4.6% and 3.0% respectively. Although the expansion of the weed was restrained by cover crops, the soil tillage prior to sowing the annual species spreads the rhizomes and stolons to weed free areas of the field. Canonical Correspondence Analysis (CCA) showed that the weed community composition varied depending on the cover crop species, revealing the importance of its management in the weed assemblage.

Effect of Mulching on Soil Quality in an Agroforestry System Irrigated with Reused Water

In this study, a special rice-energy willow/poplar agroforestry system was used to analyze the effects of reused water irrigation and mulching on soil salinity, earthworm biomass and abundance, soil organic matter (SOM) content and weed coverage in treerow-dependent habitats. After three-year-irrigation, we investigated the woody line (WL), the buffer zone (BZ) and the crop line habitats (CL). Between 2019 and 2021, we collected data on the distribution of soil-specific electrical conductivity (EC), ammonium-lactate soluble sodium (AL-Na) and exchangeable cations (Na+, K+, Ca2+, Mg2+) and soil NO2− + NO3−-N contents from CL habitats irrigated with effluent water from an intensive catfish farm. Based on our results, significantly greater earthworm abundance (274 pc m−2) and earthworm biomass (54.0 g m−2) values were measured in WL than in BZ or CL habitats. There was no significant difference in weed coverage between the CL (0.61%) and BZ (1.91%), but weeds were significantly denser on the WL (12.3%). In the third year, the EC, AL-Na and ESP values were lower, but the SOM was higher in mulched soil (183.1 mS cm−1, 253.1 mg kg−1, 4.4 ESP% and 4.597%, respectively) than in un-mulched soil.

An integrated weed management approach in tomato using soil steaming, mulching, and winter cover crops

One of the most significant yield losses in tomato (Solanum lycopersicum L.) is due to weeds. Yellow and purple nutsedge, large crabgrass, and Palmer amaranth are the most troublesome weed species in tomato production throughout the southeastern United States. This study aimed to determine the impact of soil steaming, plastic mulching, and cover crops on weed suppression, tomato height, and fruit yield. The cover crops used were hairy vetch (Vicia villosa), crimson clover (Trifolium incarnatum), and cereal rye (Secale cereale). The study was conducted at the Mississippi State University Truck Crops Experiment Station in Crystal Springs, Mississippi, USA. The experiment used a completely randomized block design with three fall cover crop treatments, including fallow, and each was replicated three times and repeated in two years. Each plot was broadcasted with a mixture of yellow nutsedge (Cyperus esculentus L.), large crabgrass (Digitaria sanguinalis L.), barnyardgrass (Echinochloa crus-galli), and Palmer amaranth [Amaranthus palmeri (S.) Watson] at a density of 20 plants m-2 for each weed species. Two days after sowing the weed seeds, the soil surface was steamed according to its assigned treatment until it reached 61°C for either 0, 5, or 20 min. After steaming, drip irrigation tubing was laid on each row, and covered by black, 0.0254-mm plastic mulch. Data were recorded in both years, including weed cover, plant height, and fruit yield. The lowest weed cover was observed at 5 min of soil steaming in mulched treatment, and the highest cover was noted at 0 min of soil steaming in the absence of mulching. Yellow nutsedge was the dominant weed species, even under steam and mulch treatments. The use of cover crops did not show a difference compared to fallow treatments. However, hairy vetch showed the lowest weed cover, followed by crimson clover. Tomato plants in steamed soil were up to 13 cm taller than those in unsteamed soils. Additionally, steaming at 5 or 20 min in combination with plastic mulch increased the marketable and cull yield. Soil steaming and mulching increased tomato plant height and yield while decreasing weed population and can, therefore, be effectively incorporated into an integrated weed management program in tomato.

Precision weed control using a smart sprayer in dormant bermudagrass turf

Precision herbicide application can substantially reduce herbicide input, thereby cutting chemical costs and minimizing adverse environmental impacts. A smart sprayer prototype was designed and developed for precision herbicide application in turf. This is the first study evaluating the performances of a precision sprayer for weed control in turf in field conditions. The objectives of this research were to 1) evaluate and compare the performances of the traditional broadcast application and a newly developed precision spraying technology for control of weeds in dormant bermudagrass turf, and 2) investigate the influence of weed coverage on the spray volume requirement when using the precision spraying technology developed here. DenseNet, GoogLeNet, and ResNet were evaluated for discriminating the grid cells containing weeds (spray) with the grid cells containing bermudagrass turf exclusively (nonspray). All three neural networks had an F1 score above 0.989 in the validation datasets. ResNet outperformed DenseNet and GoogLeNet with the highest F1 scores (≥0.992) in the testing datasets. Applying herbicide only to turf areas infested with weeds saved a significant amount of the herbicide, while achieving the same level of weed control compared to the broadcast application. The developed precision spraying technology performed well and effectively reduced the amount of herbicide input applied to the dormant bermudagrass turf, compared to the broadcast herbicide application. Overall, the smart sprayer prototype developed in this research can be used for precision weed control in dormant turf, although its design needs to be further optimized.